Mobile telephone design is constantly evolving. Originally, mobile telephones were large and bulky, and necessarily so. The radio communications equipment inside them, and the battery for providing power both had to be carried in the same unit, although in earlier designs the unit was actually separated in two and connected by a power cable for operation. Advances in the technology related to both integrated circuitry and to electricity storage devices, however, have enabled mobile telephone designers to create smaller and smaller devices. These smaller instruments are not only lighter, but less cumbersome and easier to transport. For that reason, mobile telephones no longer need to be permanently installed in automobiles or connected to a separately-carried battery pack for convenient operation. If nothing else, small mobile telephones have simply become more fashionable.
Along with the convenience, however, have come certain drawbacks. While mobile phones that are almost miniature in comparison to their larger predecessors are certainly easier to carry, they are also easier to store or transport in a pocket, briefcase, purse, or duffle bag. They are subject to being stowed in glove compartments and toolboxes, and may frequently encounter other solid objects that could potentially cause damage to them, either cosmetic or to their actual internal components. Despite this frequent rough handling, the mobile phones' small lightweight construction obviously makes it more difficult to use heavy-duty structural components to protect increasingly sensitive equipment. Modern mobile phones are in some ways simply more vulnerable to injury.
The risk of damage is exacerbated by the number of externally accessible components. Most prominently, mobile telephones now almost universally have some form of visual display. Initially, visual indicators might have been limited to small, light emitting diodes (LEDs) that indicated whether the telephone was on or a call was in progress. More advanced LED displays were then developed that were capable of displaying a dialed telephone number, the current time, or other simple information. More recently, liquid crystal displays (LCDs) have become common. An LCD is made by sandwiching an electrically sensitive liquid-crystal material in between two very thin pieces of glass or other transparent material. They are, therefore, easily susceptible to damage by even relatively minor impact. Although normally protected by a hard, transparent cover or similar protective mechanism, LCDs are still nonetheless easily damaged components in the modern mobile telephone. Although other externally-accessible components are not so easily harmed, they are nevertheless subject to damage caused by rough handling.
One solution providing more protection for the mobile phones externally-accessible components is the bifold design. A bifold mobile telephone is one that may be, generally speaking, folded in half. That is, the instrument is typically made up of at least two parts that are electrically connected together, each part housing a portion of the mobile telephones internal components. Note that herein the term “folded in half” is used in a general sense, that is, the two “halves” are not necessarily equal in size. There may even be more than two “halves” although such a design is not typical. In ordinary use, the two halves are held together by a hinge, and “opened” when the phone is actually being used to place or receive a call. Opening the phone reveals its LCD and keypad, which remain folded inside when the unit is closed for storage. Using this design, the mobile telephone may be more safely tucked into a pocket or purse, or clipped onto the user's belt, its most impact-sensitive exposed components now protected by the hard plastic case.
FIG. 1 is an illustration of a typical bifold mobile telephone according to the prior art. Mobile telephone 100 includes a first portion 110 and a second portion 150. First portion 110 of mobile phone 100 houses the LCD 115, visible through but protected by clear plastic cover 117. Speaker port 120, a series of small openings formed in first portion 110, lie adjacent to an internal speaker (not shown) that is also housed by first portion 110. First portion 110 of mobile phone 100 also typically includes the circuitry for driving the display 115 and the internal speaker.
Second portion 150 of mobile phone 100 includes a microphone port 155 formed in second portion 150 adjacent to an internal microphone (not shown). Second portion 150 also forms a plurality of openings through which the individual keys of an otherwise internally disposed key mat, form keypad 160. As with first portion 110, second portion 150 of mobile telephone 100 also houses the internal circuitry associated with these user interface devices. An antenna for facilitating radio frequency (RF) communications may be located in either first portion 110 or second portion 150, or may be distributed between them. The battery (not shown) of mobile telephone 100 is typically stored in the second portion 150, the first portion 110 being taken up largely by the LCD and speaker. An external power supply (not shown), such as an AC adaptor, may be connected through power port 140. Similarly, external headphones (not shown) may be connected to mobile phone 100 at external-device port 145.
The two sections of mobile phone 100 are held together by a hinge 175. Forming hinge 175 are hinge members 176 and 177 extending from first portion 110 and hinge members 178 and 179 extending from second portion 150. The two sections are then held together by hinge pin 180, which extends through openings formed in hinge members 176 through 179. Note that as shown in FIG. 1, mobile phone 100 is in its active operational position. When the mobile phone is thus “opened”, the user has access to the keypad and can conveniently place the speaker port and microphone port in a position for voice communication. The mobile phone 100 may also be “closed” by folding the first portion to meet the second portion in the direction of the arrow. FIG. 1B is an illustration of mobile phone 100 in the closed position. Note that the first portion 110 and the second portion 150 close in such a manner as to protect the keypad and more importantly the LCD 115. Generally speaking, the mobile telephone 100 cannot be used in this configuration, although it may be possible to do so by employing an external microphone and speaker (not shown). The external microphone and speaker are often used for ‘hands-free’ operation, and may be connected through external-device port 145. A phone thus equipped could be placed into a pocket while a call was in progress, at least until access to the keypad requires that it be opened up. As alluded to above, when in the closed position, mobile phone 100 may be placed into a belt clip device, pocket, purse, or glove compartment without fear of it being damaged by objects such as keys that it might encounter there.
As should by now be apparent, folding mobile telephones have features that are both useful and desirable. Some users may also prefer them to other designs from a purely-aesthetic point of view. The design shown in FIGS. 1A and 1B is not optimum, however, as the hinge mechanism in some cases hinders the ability of designers to make stylish modifications. The hinge also represents somewhat of a bulky addition to the otherwise compact and streamlined telephone, and must be relatively sturdy in order to avoid damage to some of its more vulnerable components, such as hinge members 176 through 179 (shown for example in FIG. 1A). It would therefore be desirable to construct a folding mobile telephone having the advantageous features of the typical mobile telephone 100 shown in FIG. 1, but without the disadvantages associated with its hinge member 175. The present invention provides just such a design.